Search notes:

gcc -H

gcc -H prints the names of each header file that is processed.
Each #include indents one level, finishing a file dedents one level. 
$ echo '#include <syscall.h>' | gcc -c -xc - -E -P -H
. /usr/include/syscall.h
.. /usr/include/x86_64-linux-gnu/sys/syscall.h
... /usr/include/x86_64-linux-gnu/asm/unistd.h
.... /usr/include/x86_64-linux-gnu/asm/unistd_64.h
... /usr/include/x86_64-linux-gnu/bits/syscall.h
Multiple include guards may be useful for:
/usr/include/syscall.h
/usr/include/x86_64-linux-gnu/bits/syscall.h

See also

GCC options

Index

Fatal error: Uncaught PDOException: SQLSTATE[HY000]: General error: 8 attempt to write a readonly database in /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php:51 Stack trace: #0 /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php(51): PDOStatement->execute(Array) #1 /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php(66): id_of(Object(PDO), 'uri', '/notes/developm...') #2 /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php(30): insert_webrequest_('/notes/developm...', 1759398357, '216.73.216.42', 'Mozilla/5.0 App...', NULL) #3 /home/httpd/vhosts/renenyffenegger.ch/httpsdocs/notes/development/languages/C-C-plus-plus/GCC/options/H_uppercase(50): insert_webrequest() #4 {main} thrown in /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php on line 51